My bro's 400ex is killing my 250R!
 

His 400 has a white bros e-series, stage II hotcam, white bros rev limiter, k&n, 36t sprocket, and 18" holeshots. He takes me all the way up through 6th gear and then I take him on top speed. What can I do to my R to get faster acceleration? I got FMF pipe/silencer, k&n, reed spacers, wiseco, 38t sprocket, and 18" tires.

My bro's 400ex is killing my 250R!
 

drop your front sprocket or go to a 40 tooth rear sprocket

My bro's 400ex is killing my 250R!
 

doesnt getting a bigger sprocket in the rear make you loose acceleration?

My bro's 400ex is killing my 250R!
 

no.. its the opposite. it it isnt the size of the rear sprocket per say that makes teh difference, its the combined ratio of teh front ANd rear sprockets. just keep in mind you get more off teh line with a smaller front sprocket and larger rear sprocket. and you get more top speed with a larger front and smaller rear. note that when you adjust your gearing to acheive better acceleration you will find that you'll be shifting alot more sooner

My bro's 400ex is killing my 250R!
 

Bigger in rear gives you a lower gear ratio, smaller in front does the same thing. You will get to your power band much quicker with the bigger rear sprocket.
You could also try running a leaner jet.
How much is he beating of the line?

Shane

My bro's 400ex is killing my 250R!
 

He beats me until he reaches top speed. When he had the stock 39 in the rear i would beat him by alot in accel and top speed, then he went down to the 36 and he got killer accel but lost top speed

My bro's 400ex is killing my 250R!
 

That makes no sence, he must have changed the size of his tires or something the same time he changed the sprocket. and a 36 is very small! Unless hes running a 10-12 front, his top speed should go way up. Unless his 400 cant pull it in 6th...

-nick

My bro's 400ex is killing my 250R!
 

when he had the 39 he had the stock 20" tires, when he got the 36 he got the 18's and he had the stock 15 in the front. So if i go up to a 14 in the front itll be like i went down to a 35 in the rear? would this give me accel or top speed? i dont care about top speed, i race mx and i need alot of acceleration.

My bro's 400ex is killing my 250R!
 

no crackhead youre thinkin wrong again.... you want to go SMALLER up front for better acceleration. ( or LARGER in the rear)

My bro's 400ex is killing my 250R!
 

so would a 12/40 be a good combination? or would that make a 20mph loss of top speed?